CSV Import

[Steve Isenberg]

Just began using GnuCash for a local non-profit group. I tried importing transaction data from CSV file. It kept failing. The documentation doesn't describe proper file format or details about CSV import. I need to eliminate manual input of data as the non-profit has revenue from multiple sources.
I did an export and examined the file contents. I have multiple questions about format and meaning of the columns.
I have multiple rows for each transaction, showing multiple categories. There is a column called 'Type'. The values are 'T' and 'S'. 

What is the 'Type' column and what is the meaning of the values?
What is the column 'Action' for and what values might it contain? 

What are the meanings of the 'To With Sym', 'From With Sym', 'To Num', 'From Num' and 'To Rate' columns? 

What rules determine what values are placed in these cells for importing data?
Your help is greatly appreciated.

Thank youSteve I